Why You Can't Trust Nutrition Research

Photo credit: Dan Dimmock

Ever wonder why one day the news touts how wonderful drinking coffee is only to later report how coffee should be restricted in your diet? You aren't going crazy and there is a valid reason as to why this is the case and it all comes back to nutrition research.....that and journalistic sensationalism.

As mentioned in my previous article, What You Need to Know About the Future of Food, nutrition research is reviewed every 5 years by the USDA to make adjustments to the dietary guildelines via systemic review. "Systemic review means that data is taken from published studies and summarized into a conclusion. It is often misleading. Nutrition data particularly is ripe for error as it is all run through...a method called AMPM (Automated Multiple Pass Method). The AMPM consists of five questions asked of a person to recollect the past 24 hours. First, recall all foods consumed then recall forgotten foods, take into account the time and occasion, describe the foods eaten (sizes, amounts, etc) then try to recall any additional foods forgotten. 100% based off human memory. Not so reliable." The research that is collected for the systemic review is also unreliable. Let's take a look at why.

Epidemiology

The study of epidemiology began in the 1800s and consists of making observations in a methodical manner to recognize a pattern and then implicate it's causation. For example, a group of women eat blueberries everyday and when tested perform at a higher IQ level than women who do not consume blueberries everyday, therefore the conclusion made is that blueberries increase your IQ. While I love blueberries, there was no real scientific method executed to concretely back up this statement (no experiment) making it still a hypothesis.

Nutritional epidemiology began being the standard use to study the link between human nutrition and chronic disease by Walter Willett, professor of the Harvard School of Public Health. He created the Food Frequency Questionnare (FFQ) which relies on a persons' memory of what they ate for the past year! Not only that, they seek specific amounts. How many ounces of meat did you consume? How many calories of vegetables did you have? FOR THE ENTIRE YEAR. I don't know about you, but I have a tough time recalling yesterday let alone everything I ate last year. Human memory is not a reliable source. Regardless, once the questionnaires are gathered the researchers will look for patterns of common food consumption and make a hypothesis as to it helping to stave off cancer or not.

There is no standard

Despite how unscientific nutrition research already is, it gets better-- there is no standard of coding or description of nutrition. When you are conducting research you would use a questionnaire that relies solely on 24 hour or even 12 month memory, the amount of food intake measurement varies exorbitantly and how could it not since you are relying on individual perspective. One viewpoint of a large steak could be a 12 oz cut, whereas another could be 16 oz. There is a distinct difference in amount of protein intake and other minerals within that 4 oz difference.

To add to this discrepancy, there are other factors that add systematic bias such as differing BMI's, varying age of participants, as well ethnicity that need to be accounted for when utilizing analytical epidemiology of nutrition. Thankfully the field is starting to take advantage of technology by having people take pictures to minimize the differing perspective, however there are other variables that need to be addressed.

What next?

Dr. Georgia Ede lays out in her article, The Problem with Epidemiological Studies:

"Nutrition epidemiology research isn’t about changing people’s diets to see what happens. Instead, researchers give people questionnaires about their health and eating habits, then look for patterns in the answers to see if they can find connections—associations—between certain foods and certain diseases. Based on their observations, they generate a hypothesis—a guess—about how a particular food and a particular disease may be related. These guesses easily find their way into the popular media long before they are tested in experiments, generating headlines that often make it sound as if those guesses are scientific facts you can use to make healthier decisions about your diet. Simply put, nutrition epidemiologists jump to conclusions—and journalists, nutrition policymakers, and the general public jump right along with them.

When nutritional epidemiology hypotheses are later put to the test in clinical trials, they have been shown to be wrong at least 80% of the time."

The cost of randomized, controlled dietary intervention is expensive and part of the reason research has been conducted the way it has so far. It is difficult to restrict a large group of people to a specific diet for the long term, which the research would need to be conducted for at least a decade due to the fact that researchers need to rule out other factors such as medication influence on chronic disease. All of this for one specific alteration.

There is a push towards utilizing biomarkers, such as blood and urine, to track nutritional influence. The one drawback of these are 1. they are influenced by short term dietary changes and 2. the need to develop more biomarkers (tests). One answer to both of these issues is to gather periodic data from the biospecimens over the long term and analyze that to come to a median marker. To put this into perspective think of getting your blood pressure taken, your blood pressure can be elevated due to lack of sufficient sleep, sickness, white coat syndrome, etc. To make a conclusive statement of your health status based off of one blood pressure measurement does not give a true reading. If you take your blood pressure periodically, say every month then add those up to find the median range you will get a better idea of what your blood pressure typically is. Same for the gathering of metabolic condition based of biomarkers.

Before I go I want to stress that the association of genetics in chronic disease is an extremely weak link. The fact that you shared in a similar diet as well as activities as your family has been observed as the common denominator to attempting the genetic link explanation for chronic disease. It is the shared environment versus the genes that leads to common expression of chronic disease. This means you  change the environment and your risk of expressing the chronic disease decreases.
As I've stated in the past, DNA loads the gun but lifestyle pulls the trigger.

What next?

Contact me and let's review your current nutritional status, find out exactly what you need to be the healthiest you. Looking forward to discussing with you and helping you progress to the next stage!

References

1. https://www.diagnosisdiet.com/full-article/epidemiological-studies
2. https://pubmed.ncbi.nlm.nih.gov/23443832/
3.https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6377194/